The RED12 Omni Condenser Microphone is made from shotgun shells!
"TheRED12Microphone is perfect for drum overheads and acoustic instruments such as guitar, mandolin, and violin. The custom assembly achieves the dependable and consistent performance you need for recording inside a compact, aesthetically pleasing shell that is as unique as it is bad ass. These omni microphones are built into an actual spent 12-gauge shotgun shell casing!" Talk about goingGREEN! http://www.12gaugemicrophones.com/